Carbon acidity. 79. Acidity of enolate equivalent compounds: oxime ethers
摘要:
A series of benzylic oxime ethers were synthesized (CH3ON = C(CH2Ar)2, Ar = phenyl (1), 4-biphenylyl (2), 1-naphthyl (3)), and the equilibrium ion pair acidities in THF were determined. The lithium ion pair acidity of 1 was found to be approximately 5 pK units lower than the corresponding cesium ion pair acidity. The oxime ethers are approximately 10 orders of magnitude less acidic than their corresponding ketones for cesium ion pairs. Thermodynamic parameters for the equilibrium acidities were measured and are consistent for contact ion pair monomers being the important species in solution. An aggregation study also indicates that these cesium oxime ether enolates exist mainly as ion pair monomers. The role of the gegenion in the stability of oxime ether anions is discussed.
A rubber composition comprising a compound having one or more groups represented by formula (X) and a rubber component is provided.
wherein ring W
1
represents a cyclic group having at least one selected from the group consisting of —C(═O)— and —C(═S)—; N
10
represents a nitrogen atom; the at least one selected from the group consisting of —C(═O)— and —C(═S)— in the ring W
1
and N
10
are conjugated; and Z
1
represents —O— or —S—.
The reduction of dibenzylketoxime (Ia) with LAH in boiling THF gave cis-2-phenyl-3-benzyl-aziridine (IIa) in excellent yield, together with a small amount of the expected primary amine, 2-amino-1,3-diphenylpropane (III). The LAD reduction of Ia was carried out and the position of deuterium introduced was based on the NMR data. The O-substituted derivatives of Ia, such as O-Me, O-acetyl and O-tosyl
A rubber composition comprising a compound having one or more groups represented by formula (X) and a rubber component is provided.
wherein ring W1 represents a cyclic group having at least one selected from the group consisting of —C(═O)— and —C(═S)—; N10 represents a nitrogen atom; the at least one selected from the group consisting of —C(═O)— and —C(═S)— in the ring W1 and N10 are conjugated; and Z1 represents —O— or —S—.
CIULA, JAMES C.;STREITWIESER, ANDREW, J. ORG. CHEM., 56,(1991) N, C. 1989-1993
作者:CIULA, JAMES C.、STREITWIESER, ANDREW
DOI:——
日期:——
Carbon acidity. 79. Acidity of enolate equivalent compounds: oxime ethers
作者:James C. Ciula、Andrew Streitwieser
DOI:10.1021/jo00006a007
日期:1991.3
A series of benzylic oxime ethers were synthesized (CH3ON = C(CH2Ar)2, Ar = phenyl (1), 4-biphenylyl (2), 1-naphthyl (3)), and the equilibrium ion pair acidities in THF were determined. The lithium ion pair acidity of 1 was found to be approximately 5 pK units lower than the corresponding cesium ion pair acidity. The oxime ethers are approximately 10 orders of magnitude less acidic than their corresponding ketones for cesium ion pairs. Thermodynamic parameters for the equilibrium acidities were measured and are consistent for contact ion pair monomers being the important species in solution. An aggregation study also indicates that these cesium oxime ether enolates exist mainly as ion pair monomers. The role of the gegenion in the stability of oxime ether anions is discussed.